An opportunistic packet transmission scheme for MIMO based wireless sensor networks

In this paper, we consider a MIMO wireless sensor network model with single hop architecture, which consists of both a central control node and sensor nodes having multiple antennas. In our system model, we concentrate on single beam opportunistic communication and propose a novel MAC protocol that can perform multiuser diversity gain based on effective SNR (ESNR) metric with the aid of selection combining technique. Packet transfer from sensor nodes to control node is initiated when the channel quality of any node exceeds the predefined threshold. In order to maximize the system performance, we find an optimum threshold for packet transmission decision of sensor nodes. The problem of finding the optimum threshold is formulated using the probability of successful packet reception at the control node. The performance of the suggested MAC protocol is demonstrated through Monte Carlo simulations for Rayleigh slow fading channel model.